Design, development and in vitro evaluation of Mesalamine tablets containing Pectin and Chitosan for colon-specific drug delivery

The potential of matrix, multilayer and compression coated tablets of Mesalamine to reach the colon intact has been investigated in vitro, using Pectin as a carrier. Matrix tablets containing various proportions of Pectin were prepared by wet granulation and direct compression techniques. Multilayer tablets were formulated using Pectin as release controlling layers, on either side of Mesalamine matrix tablets. Mesalamine core tablets were prepared and compression coated with Pectin. The effect of the coat: core ratio as well as the incorporation of different percentages of Chitosan in the Pectin coat on drug release was investigated. In vitro release studies indicated that matrix and multilayer tablets failed to control the drug release in the physiological environment of stomach and small intestine. Compression coated formulations were able to protect the tablet cores from premature drug release, but at high Pectin coat: core ratios 4: 1 (F13) and 5: 1 (F14). Inclusion of Chitosan 3% and 5% w/w (F11 and F12) in the Pectin coat offered better protection at a lower coat: core ratio (3: 1). Selective delivery of Mesalamine to the colon could be achieved using a Pectin or Pectin/Chitosan mixture in the form of compression coated tablets.